Application of strain-life fatigue-corrosion model for fillet-welded connections of sign support structures

2020 ◽  
Vol 23 (12) ◽  
pp. 2642-2652
Author(s):  
Hyungjoo Choi ◽  
Husam Najm
Keyword(s):  
Fatigue Testing ◽  
Low Carbon Steel ◽  
Fatigue Threshold ◽  
Chemical Compositions ◽  
Support Structures ◽  
Low Carbon ◽  
Threshold Values ◽  
Constant Amplitude ◽  
Corrosion Model ◽  
Sign Support Structures

Fatigue-related corrosion is a complex phenomenon that induces damage accumulation and electrochemical deterioration throughout the service life of the structure. This article presents a previously proposed and modified strain-life Smith–Watson–Topper corrosion model for details on fillet-welded connection of highway sign support structures. To evaluate the degree of corrosion activity, hot-dip galvanized, weathering, and low-carbon steel are investigated with respect to chemical compositions, material properties, and the corresponding corrosion resistance indices. The existing fatigue testing data were analyzed and used to evaluate fatigue resistance under various corrosion environments. A modified Smith–Watson–Topper corrosion model is further utilized to determine acceptable constant amplitude fatigue thresholds for the American Association of State Highway and Transportation Officials fatigue limits under each corrosion category. It was found that low constant amplitude fatigue threshold values were observed for ASTM A588, A595, and A572 steels in locations with corrosion categories exposed to severe corrosive environments. Under these conditions, hot-dip galvanization or other surface treatments of the steel components of the sign supports are recommended to achieve higher constant amplitude fatigue threshold values.

scholarly journals Fatigue threshold and closure in duplex low carbon steel.

1988 ◽  
Vol 37 (420) ◽  
pp. 1077-1083 ◽  
Author(s):  
Keiji OGURA ◽  
Yoshio MIYOSHI ◽  
Izuru NISHIKAWA ◽  
Yasutaka NAKAO
Keyword(s):  
Carbon Steel ◽  
Low Carbon Steel ◽  
Fatigue Threshold ◽  
Low Carbon

High-Cycle Fatigue and Thermal Dissipation Investigations for Low Carbon Steel Q345

2015 ◽  
Vol 664 ◽  
pp. 305-313 ◽  
Author(s):  
Han Qing Liu ◽  
Qing Yuan Wang ◽  
Zhi Yong Huang ◽  
Zhen Jie Teng
Keyword(s):  
Carbon Steel ◽  
High Cycle Fatigue ◽  
Fatigue Testing ◽  
Low Carbon Steel ◽  
Infrared Camera ◽  
Fatigue Property ◽  
Thermal Dissipation ◽  
Loading Frequency ◽  
Cycle Fatigue ◽  
Low Carbon

Carbon steel is a kind of metallic material that widely used in construction, machinery, manufacturing and other domains. In the mechanical structure system, long-term cyclic stress may cause the mechanical components failure. In this work, the characteristic of fatigue crack propagate in low carbon steel Q345 and the effect of loading frequency to the fatigue property of Q345 steel were investigated. Meanwhile, the dispersion of high-cycle fatigue of life of the Q345 steel under high fatigue testing frequency was analyzed, and the P-S-N curve with the test data was given out. With the help of infrared camera, temperature rise curve during fatigue test was analyzed to study the thermal dissipation of Q345 steel.

The Rate of Growth of Fatigue Cracks

1936 ◽  
Vol 3 (1) ◽  
pp. A23-A25
Author(s):  
A. V. deForest
Keyword(s):  
Fatigue Crack ◽  
Iron Oxide ◽  
Carbon Steel ◽  
Fatigue Testing ◽  
Fatigue Cracks ◽  
Low Carbon Steel ◽  
Low Carbon ◽  
Rate Of Growth ◽  
Steel Bars ◽  
Cold Rolled

Abstract The author discusses the resistance of metal to the propagation of cracks, and points out that in the accepted method of fatigue testing the results are not conclusive because there is no distinction between (1) the load and the number of repeated stresses required to start cracks and (2) the load and the number of reversals needed to propagate the cracks to failure. The investigation reported in the paper was undertaken to determine (a) the stress and number of reversals required to start a fatigue crack, and (b) the resistance of the material to the effect of a fatigue crack once it had been formed. The tests reported were conducted on annealed cold-rolled low-carbon steel bars with various finishes. The author presents data on the rate of progress of the cracks and on the size of the cracks, the latter of which was determined by magnetizing the bars and inspecting them with finely divided iron oxide in a bath of kerosene.

Developing High Strength-High Toughness Low Carbon Steel Using Combined V-Ti-Micro-Alloying and Different Thermo-Mechanical Treatments

2018 ◽  
Vol 786 ◽  
pp. 57-64 ◽  
Author(s):  
Ahmed Hamed ◽  
Mamdouh Eissa ◽  
Abdelhakim Kandil ◽  
Omnia Ali ◽  
Taha M. Mattar
Keyword(s):  
Tensile Strength ◽  
Carbon Steel ◽  
Impact Toughness ◽  
Low Carbon Steel ◽  
Chemical Compositions ◽  
Air Cooling ◽  
Low Carbon ◽  
Steel Alloys ◽  
Grain Sizes ◽  
The Impact

This work aims at designing and developing low carbon steel alloys to meet the high tensile strength, high ductility and high impact toughness properties. The effect of solid solution mechanism, precipitation hardening, as well as grain refinement were developed with different Manganese content (0.78-2.36wt%) combined with Vanadium(0.008-0.1wt%) and Titanium (0.002-0.072wt%) microalloying additions. The controlled thermo-mechanical treatments and chemical compositions play a big role in developing the microstructure and the corresponding mechanical properties. Therefore, the studied chemical compositions were treated thermo-mechanically by two different ways of changing start and finish forging temperatures with subsequent air cooling. The first way by start forging from 1050 to 830oC and the second from 950 to730oC. The second way of forging process developed finer grain sizes and higher ultimate tensile strengths for all the studied steel alloys. In spite of finer grain sizes, the impact toughness value was lower in the second regime due to detrimental influence of precipitation strengthening in the ferrite. A combination of 544 MPa yield strength, 615 MPa ultimate tensile strength, 20% elongation and 138 Joule impact toughness has been attained.

Prediction of the Mechanical Properties of Hot-Rolled Low Carbon Steel Strips in Correlation to Chemical Compositions and Rolling Conditions

2011 ◽  
Vol 462-463 ◽  
pp. 401-406 ◽  
Author(s):  
Jiratthanakul Noppon ◽  
Somrerk Chandra-ambhorn
Keyword(s):  
Mechanical Properties ◽  
Carbon Steel ◽  
Steel Strip ◽  
Low Carbon Steel ◽  
Chemical Compositions ◽  
Low Carbon ◽  
Coiling Temperature ◽  
Empirical Formulas ◽  
The Difference ◽  
Hot Rolled

Seven thousand sets of data consisting of mechanical properties, chemical compositions, and rolling parameters of industrial hot-rolled coils were analysed using multiple regression. This was to establish empirical formulas to predict mechanical properties of steel as a function of chemical compositions and rolling parameters. The empirical formulas predicting yield strength (YS), ultimate tensile strength (UTS) and percentage of elongation (EL) of low carbon steel strip were obtained, e.g. YS = 461+ 418 C + 61.6 Mn + 796 P ¬– 303 S + 159 Si + 146 Cu + 204 Ni + 49.7 Cr + 1127 V + 1072 Ti + 3674 Nb – 266 Mo – 6299 B – 76.3 Al – 557 Sn – 3.54 THK – 0.00758 WID – 0.114 FT – 0.223 CT. The rolling parameters in equation included finishing temperature (FT), coiling temperature (CT), thickness (THK) and width (WID) of strip. R-Square values for the formulas predicting YS, UTS, and EL were 82.3%, 90.1%, and 75.8% respectively. These equations were validated by using another 120 hot-rolled coils. The averages of absolute values of the difference between the predicted and actual values of YS, UTS, and EL were 9.6 MPa, 7.8 MPa, and 2.7 % respectively. Correlation of chemical compositions and rolling conditions with mechanical properties was discussed in the paper.

Prediction of Fatigue Threshold of Notched Components

1984 ◽  
Vol 106 (2) ◽  
pp. 192-199 ◽  
Author(s):  
K. Tanaka ◽  
Y. Nakai
Keyword(s):  
Experimental Data ◽  
Stress Intensity ◽  
Low Carbon Steel ◽  
Fatigue Threshold ◽  
Low Carbon ◽  
Stress Intensity Range ◽  
Intensity Range ◽  
Effective Stress Intensity Range ◽  
Consistent Method ◽  
Tip Radius

A consistent method is proposed to predict significant properties concerning the notch fatigue threshold from three experimental data: the fatigue limit of smooth specimens, the threshold stress intensity range for a long crack, and the effective stress intensity range at the threshold for a long crack. Based on the model of the intrinsic crack combined with crack closure, the fatigue limits for crack initiation and fracture from a notch, the length of a nonpropagating crack, and the notch tip radius at the branch point are all derived in a consistent way. The predicted results are compared with the experimental data of a low-carbon steel, and good agreement is obtained.

Magnetic Microscopic Evaluation of Early-Stage Fatigue in WMZ (Weld Metal Zone) of Low Carbon Steel Plates (JIS, SS400)

2011 ◽  
Vol 255-260 ◽  
pp. 4186-4192 ◽  
Author(s):  
Katsuyuki Kida ◽  
Takashi Honda ◽  
Edson Costa Santos ◽  
Kenichi Saruwatari ◽  
Megumi Uryu ◽  
...  
Keyword(s):  
Carbon Steel ◽  
Magnetic Fields ◽  
Fatigue Testing ◽  
Low Carbon Steel ◽  
Steel Plates ◽  
Hall Probe ◽  
Low Carbon ◽  
Welding Joint ◽  
Cyclic Stresses ◽  
Microscopic Evaluation

Cyclic stresses around welding joint-part affect the strength of mechanical components. In order to understand the fatigue phenomena caused by the cyclic stresses, non-destructive methods that can be related to number of stress cycles are necessary. In the present work, we used a newly developed scanning Hall probe microscope (SHPM) equipped with a GaAs film sensor and observed three dimensional magnetic fields of the specimen before and after four point fatigue testing at room temperature in air. Low carbon steel plates (JIS, SS400) were used in the experiments. It was found that the intensity of the magnet field in a direction perpendicular to the specimen surface was strongly affected by the fatigue testing. This result means that we can evaluate the fatigue in welding-joint area using quantitative magnetic field measurements. Furthermore, it was discovered that the key factor to evaluate the fatigue is the range between “S” and “N” (“peak-to-bottom” values) of the magnetic fields.

scholarly journals Investigation on Fatigue Threshold Testing Methods in a Near Lamellar TiAl Alloy

Materials ◽  
2019 ◽  
Vol 12 (21) ◽  
pp. 3487
Author(s):  
Shiyuan Wang ◽  
Hangyue Li ◽  
Paul Bowen
Keyword(s):  
Tial Alloy ◽  
Fatigue Testing ◽  
Fatigue Loading ◽  
Load Shedding ◽  
Fatigue Threshold ◽  
Threshold Values ◽  
Tial Alloys ◽  
Testing Procedures ◽  
Crack Wake ◽  
Electro Discharge Machining

The effects of influential fatigue testing factors, including loading schemes (e.g., traditional load shedding and staircase load increasing), morphology of crack starters, and precracking approaches on the near-threshold fatigue crack growth behaviors for a near lamellar γ-TiAl alloy (Ti-45Al-2Mn-2Nb-1B) were investigated at room temperature and 650 °C. The results showed that the measured fatigue threshold values in lamellar γ-TiAl alloys are very sensitive to the applied testing procedures. For example, the staircase load-increasing method yielded smaller threshold values. When such a load-increasing method was used, the threshold values were measured either from a notch machined by electro-discharge machining or prepared by a compression–compression fatigue loading. Moreover, some differences could be seen with respect to the morphologies of the crack starters. Most of the above influences are associated with the brittle nature of the material and the characteristics of the lamellar microstructures, and closure effects are primarily induced by crack wake roughness or unbroken ligaments.

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